System and method for inductive charging with improved efficiency

ABSTRACT

A charging system for charging an electric vehicle comprises an inductor-inductor-capacitor (LLC) battery charger that includes an isolation transformer having a transformer primary and a transformer secondary, the transformer primary included in an inductive charger station of the charging system and the transformer secondary included in an inductive power receiver of the charging system, with the inductive power receiver positioned on the electric vehicle. The LLC battery charger also includes a magnetizing inductor circuit element and a leakage inductor circuit element integrated into the isolation transformer on the transformer primary. The isolation transformer is constructed such that the transformer primary and the transformer secondary are separable from one another, with a selective engaging and disengaging of the transformer primary and the transformer secondary based on movement of the inductive power receiver on the electric vehicle relative to the inductive charger station.

CROSS REFERENCE TO RELATED APPLICATION

The present invention is a non-provisional of, and claims priority to,U.S. Provisional Patent Application Ser. No. 62/477,151 filed Mar. 27,2017, the disclosure of which is incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION

Embodiments of the invention relate generally to electric vehiclecharging and, more particularly, to a system and method for inductivecharging of an electric vehicle that provides high efficiency inductivecharging. The inductive charging of the vehicle is achieved via a systemthat is minimally intrusive—both aesthetically and from aninfrastructure perspective—to a surrounding environment, and is providedvia an autonomous interaction between the electric vehicle and acharging station that provides self-alignment and mating between theelectric vehicle and the charging station.

Electric vehicles (EVs) provide a zero-emissions solution fortransportation in cities and, in the future, are expected to graduallyreplace the internal combustion engine vehicle as the primary mode oftransportation. Electric vehicles are configured to use electricalenergy from an external source to recharge the traction battery thereof,and thus include circuitry and connections to facilitate the rechargingof the traction battery from the utility grid or another externalsource, for example. Typically, these circuitry and connections includea plug-in by which the electric vehicle is connected to the utility gridto receive such charging power.

Unfortunately, it is recognized that a large percentage of electricvehicle owners do not have the ability to charge at home, due to lack ofan electrical outlet or space for a charger—with electric vehicle ownerswho live in an apartment or condominium complex being primary examples.That is, traditional corded plug-in or “hot contact” chargers may oftennot be available at parking lots and parking garages of an apartment orcondominium complex due to concerns of the apartment/condominium ownerregarding aesthetic issues (e.g., presenting a “gas station”-likeappearance due to multiple charging pedestals), safety/security issues(e.g., exposed cords being vandalized or stolen for the scrap value ofcopper inside the cords), and/or longevity and upkeep issues (e.g.,degradation of electrical contacts due to exposure to the environment,resulting in maintenance/replacement costs and a potential spark hazardto adjacent gasoline fueled vehicles). Further, corded chargers must behandled by a person at the beginning and end of each day (unplugged andplugged) to keep the battery at a good state of charge on the electricvehicle, which may be time consuming, inconvenient, and potentiallyforgotten by a user, thereby resulting in a car that is out of charge inthe morning.

As an alternative to corded plug-in chargers, inductive charging hasbeen used to recharge electric vehicles. Early inductive chargingsystems for electric vehicles used inductive paddles to solve potentialsafety and degradation issues typically associated with plug-inchargers. However, these inductive paddles did not address cord issuesor charging convenience issues and also resulted in lower chargingefficiency as compared to plug-in chargers (e.g., about 85%). Morerecently, modern inductive electric vehicle chargers have been designedthat provide low-clutter, ground-mount charging that is an aestheticimprovement over corded charging stations and impervious to chemicalsand electrically safe, as there are no exposed galvanic connections tocreate a shock or spark hazard. The modern inductive charging systemsare also hands-free, but the spacing of the inductive transfer coils, toaccommodate suspension travel and misalignment on other axes, results inreduced electrical transfer efficiencies (i.e., charging efficiencies)wherein twice as much energy is lost during the transfer as compared tothe best hot contact chargers. Thus, state-of-the-art inductive chargingefficiency may be in the low nineties, which is less than the 94-97%charging efficiency that is desirable and that is achievable via cordedplug-in chargers (e.g., 93% vs 96.5%).

Another recent way to obtain hands free autonomy with high transferefficiency is use of a robot function in the charger to align a hotcontact connection with the charge port on a stationary vehicle. Thisdoes not solve the environmental robustness issues with hot contacts,and adds cost, reliability concerns and possibly more clutter to thealready crowded urban environment.

Therefore, it is desirable to provide a hands-free, ground-levelinductive charger that would be well suited to uncontrolled parkingenvironments (like apartment parking lots and public garages) forovernight charging and is durable enough to withstand environmentalfactors. It is further desirable for the charging of the electricvehicle to make use of the precision of autonomous vehicle parking andmodern circuit topologies, such that the ground-level inductive chargersmay be as efficient as corded plug-in chargers in charging the electricvehicle.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with one aspect of the present invention, a chargingsystem for charging an electric vehicle comprises aninductor-inductor-capacitor (LLC) battery charger that includes anisolation transformer having a transformer primary and a transformersecondary, the transformer primary included in an inductive chargerstation of the charging system and the transformer secondary included inan inductive power receiver of the charging system, with the inductivepower receiver positioned on the electric vehicle. The LLC batterycharger also includes a magnetizing inductor circuit element and aleakage inductor circuit element integrated into the isolationtransformer on the transformer primary. The isolation transformer isconstructed such that the transformer primary and the transformersecondary are separable from one another, with a selective engaging anddisengaging of the transformer primary and the transformer secondarybased on movement of the inductive power receiver on the electricvehicle relative to the inductive charger station.

In accordance with another aspect of the present invention, a chargingsystem for inductively charging an electric vehicle comprises aninductive charger station including a docking head comprising atransformer primary having a magnetizing inductor circuit element and aleakage inductor circuit element integrated therein and a base componentcoupled to the docking head, the base component comprising powerconversion circuitry configured to provide a conditioned input power tothe transformer primary. The charging system further comprises aninductive power receiver separate from the inductive charger station,the inductive power receiver including a transformer secondaryselectively mateable with the transformer primary based on movement ofthe inductive power receiver relative to the inductive charger stationand a rectification circuit configured to provide a conditioned DCoutput power for recharging the electric vehicle.

Various other features and advantages will be made apparent from thefollowing detailed description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate preferred embodiments presently contemplated forcarrying out the invention.

In the drawings:

FIGS. 1A and 1B are pictorial diagrams of a charging system for chargingelectric vehicles, according to an embodiment of the invention.

FIG. 2 is a circuit schematic diagram of the inductive charger stationand vehicle on-board inductive power receiver included in the chargingsystem of FIGS. 1A and 1B, according to an embodiment of the invention.

FIGS. 3-8 are views of the inductive charger station and vehicleon-board inductive power receiver, and components thereof, included inthe charging system of FIGS. 1A and 1B, according to an embodiment ofthe invention.

FIG. 9 is a block schematic diagram of an autonomous vehicle mateablewith the inductive charger station of FIGS. 1A and 1B, according to anembodiment of the invention.

DETAILED DESCRIPTION

Embodiments of the invention are directed to a system and method forinductive charging of an electric vehicle that provides high efficiencyinductive charging. The inductive charging of the vehicle is achievedvia a system that is minimally intrusive—both aesthetically and from aninfrastructure perspective—to a surrounding environment, and is providedvia an autonomous interaction between the electric vehicle and acharging station that provides self-alignment and mating between theelectric vehicle and the charging station.

Referring first to FIGS. 1A and 1B, the infrastructure of a chargingsystem 10 is illustrated according to an embodiment of the invention.Charging system 10 includes a plurality of inductive charger stations 12configured to provide inductive charging to respective electric vehicles14 that may be positioned to mate therewith, with one vehicle 14 beingshown in FIGS. 1A and 1B. In an exemplary embodiment, an inductivecharger station 12 is provided for a number of respective parking spotsin which vehicles 14 may be parked for an extended period of time, suchas overnight parking in an apartment or condominium parking lot forexample. As will be explained in greater detail below, the inductivecharger stations 12 are constructed so as to be relatively flush withthe ground when not in use and then translate to an upright, raisedcharging position when a vehicle 14 comes into the immediate proximitythereof and a charging of the vehicle is desired or requested, with theinductive charger station 12 mating with an inductive power receiver 16of the vehicle 14 that, according to one embodiment, may be mountedbeneath the rear bumper of the vehicle. FIG. 1B illustrates oneinductive charger station 12 in the raised position (where vehicle 14 ispresent) and the other inductive charger stations 12 in the downposition.

As further shown in the illustrated embodiment of FIG. 1A, the chargingsystem 10 also includes an AC-DC power converter 18 that provides powerto each of the inductive charger stations 12 via a DC bus 20. In anexemplary embodiment, the AC-DC power converter 18 comprises a single,wall-mounted panel positioned near the AC utility feed circuit breakerpanel 22 (i.e., utility panel) so as to provide for easy connectionthereto. The bulk AC-DC conversion elements of the power converter 18are fed with a minimum number of AC circuit breakers, thereby conservingspace in the utility panel. The AC-DC power converter 18 may operate,for example, as a 12 kW AC to ˜400 V DC wall panel to feed the multipleinductive charger stations 12, with the addition/connection ofadditional inductive charger stations 12 being enabled with noadditional interaction with the utility panel 22. According to oneembodiment, the AC-DC power converter 18 can manage charge profiles forall connected charger stations 12 according to historical use patternswith event specific overrides, so as to maximize utilization of thepower distribution infrastructure.

In providing charging to an electric vehicle 14, an inductive chargerstation 12 mates with the inductive power receiver 16 of a dockingvehicle to form a single transformer that can be assembled each time anelectric vehicle 14 parks and can be disassembled each time an electricvehicle 14 departs. Referring now to FIG. 2, a circuit schematic diagramof the inductive charger station 12 and of the on-board inductive powerreceiver 16 of the vehicle 14 are provided to better illustrate thetransformer arrangement, as well as the power conversion electronicsincluded in the inductive charger station 12 and the inductive powerreceiver 16, according to an embodiment of the invention.

As shown in FIG. 2, an inductor-inductor-capacitor (LLC) resonanthalf-bridge converter circuit 24—which can also be referred to herein asan LLC battery charger—is provided that includes an input stage 26 andan output stage 28. The input stage 26 of the LLC resonant circuit 24 isincluded in the inductive charger station 12 and is connected to a DCbus 30 to receive DC power therefrom. The DC bus 30 may include acapacitor or capacitor bank 32 that provides smoothing to the input DCpower provided to circuit 24, such as from the wall mounted AC-DC powerconverter 18 (FIG. 1A), for example. In one example, such as whenproviding power to an interleaved transformer arrangement consisting oftwo instances/arrangements of circuit 24, the DC bus may comprise twoindependent 400V busses that can be derived from two independent boostcircuits typically running off single phase circuits, or from a +/−400Vsystem (i.e., AC-DC power converter 18) running off a 480V three phaseservice, as will be explained in greater detail below.

The input stage 26 includes a plurality of switches 34 and diodes 36that, as demonstrated in the example of FIG. 2, are arranged as ahalf-bridge circuit. According to one embodiment, the switches 34 may bein the form of metal oxide semiconductor field effect transistors(MOSFETs) that are controlled by switching signals received from ahalf-bridge controller 38 in order to output an alternating voltagesuitable for transferring power through a transformer, although it isrecognized that other suitable solid-state switches could instead beemployed—including insulated gate bipolar transistors (IGBTs), bipolarjunction transistors (BJTs), integrated gate-commutated thyristors(IGCTs), gate turn-off (GTO) thyristors, or Silicon ControlledRectifiers (SCRs), for example. While the LLC resonant circuit 24 isshown in FIG. 2 as including a half-bridge circuit, it is recognizedthat other topologies could be utilized, including a full bridgecircuit, for example.

As shown in FIG. 2, the input stage 26 includes a primary side 40 of anintegrated transformer 42 that is configured to conduct a primaryresonant current in response to the activation and deactivation of theMOSFETs 34. The input stage 26 also includes a pair of resonancecapacitors 44 that, in the illustrated embodiment, are provided as asplit resonance capacitor, so as to reduce the current stress in eachcapacitor and, in certain conditions, any initial imbalance of thevoltage applied to the transformer 42 at start. However, it is to beunderstood that the input stage 26 could alternatively just include asingle one of the pair of resonance capacitors 44, positioned at anoutput of MOSFETs 34.

In the example of FIG. 2, the integrated transformer 42 includes amagnetizing inductor circuit (L_(M)) 46, a leakage inductor circuit(L_(r)) 48, and a primary winding 50 (that provides an inductivecoupling with a secondary winding 52), with the magnetizing inductorcircuit 46 and leakage inductor circuit 48 being integrated into thetransformer to form an “integrated magnetic.” According to an embodimentof the invention, the leakage inductor circuit 48 is integrated into themain transformer 42 and replaces the resonance function (i.e., discreteresonant inductance) of the inductor circuit 46 with leakage inductance,arranging that leakage in a high power transformer that separates eachtime the inductive power receiver 16 of electric vehicle 14 disengagesfrom inductive charger station 12 and assembles each time the inductivepower receiver 16 of electric vehicle 14 mates with the inductivecharger station 12. More specifically, the geometry and arrangement ofintegrated transformer 42 is controlled and provided such that a desiredratio of L_(M) to L_(r) is provided—with L_(M) being recognized as a“parasitic” and L_(r) being a result of the geometry/arrangement of thetransformer.

According to one embodiment, the inductive charger station 12 andinductive power receiver 16 may comprise two integrated transformers 42rather than the single integrated transformer 42 shown in FIG. 2. Insuch an embodiment, the two transformers 42 may be provided as aninterleaved transformer arrangement including a pair of transformers fedby a pair of primary circuits 24 feeding a set of secondaries 54 thatcombine the voltage once inside the car, with the transformers 42 beingseparable—i.e., separable primary and secondary transformer sides foreach transformer, based on the inclusion of primary side 40 in inductivecharger station 12 and a secondary side 54 in inductive power receiver16 for each transformer. The integrated transformers 42 may thus includea pair of interleaved primary transformer halves, where one transformerdelivers 3 to 6 kW and the other transformer also delivers 3 to 6 kW,causing the pair to deliver 6 to 12 kW—with 3.6/7.2 kW and 5/10 kWdeliveries being suitable power levels provided by the transformerhalves, for example. In practice, one or two transformer halves may beprovided in inductive charger station 12 and inductive power receiver 16(as will be explained in greater detail below), with the transformer(s)thus delivering half power or full power depending on the chosenconstruction of inductive charger station 12 and inductive powerreceiver 16.

As further shown in FIG. 2, the output stage 28 of LLC resonant circuit24 is included in the inductive power receiver 16 of electric vehicle14, as part of a vehicle charger circuit, and is configured to conductan output voltage and current for recharging of one or more energystorage devices (not shown) on the vehicle 14. In response to theoscillation of the primary resonant current through the primary winding50, the secondary winding 52 of the transformer 42 that is included inthe output stage 28 generates the output current based on the magneticflux through the core of the transformer. In the example of FIG. 2, theoutput stage 28 includes an arrangement of diodes 56 and capacitors 58that condition the output current in a desirable manner, i.e.,rectification and filtering, for example, to provide an appropriate DCpower for recharging the electric vehicle 14. However, it is recognizedthat there are many different arrangements of diodes or switches thatcan be implemented for transformer waveform rectification, and thespecific arrangement of output stage 28 in FIG. 2 is shown merely forreasons of clarity. For example, an arrangement of solid-state switchessuch as synchronous FETs or IGBTs could be implemented in the outputstage 28 for performing rectification, and it is recognized that varioustypes of active or passive rectification methods could be performed byoutput stage 28.

With regard to the construction of the LLC resonant half-bridgeconverter circuit 24 illustrated in FIG. 2, the integration of theleakage inductor circuit 48 (and magnetizing inductor circuit 46) intothe main transformer 42, and the arranging of leakage inductance in ahigh power transformer that separates and assembles based on theengaging/disengaging of the primary 50 and secondary 52 of the inductivecharger station 12 and inductive power receiver 16, respectively,enables a highly efficient inductive charging of the electric vehicle14. That is, it is recognized that bumper covers and other plasticelements that cover inductive charger station 12 and inductive powerreceiver 16 are essential for providing protection thereto andincreasing the longevity thereof (e.g., to provide for 10,000 chargingcycles of operation), but that the separation in the magnetic structure(i.e., primary 50 and secondary 52 of transformer 42) caused by theseplastic coverings prevents ideal coupling and creates leakageinductance. The construction of the LLC resonant converter circuit 24 issuch that this separation in the magnetic structure and the intrinsicleakage inductance created thereby is treated as beneficial, as itallows for the foregoing of a discrete resonant inductor in the circuitand instead utilizes the single assembled magnetic structure toestablish resonance. Specifically, the leakage inductor circuit 48operates to smooth an input current received thereby and generate aneasy to manage sinusoidal current waveform that allows for a separationof the transformer primary and secondary 50, 52 in the respectiveinductive charger station 12 and inductive power receiver 16, using theleakage inductance to establish resonance. It is recognized that theleakage inductance is a function of the intrinsic specific geometry ofthe separable transformer 42, with the geometry thereof affecting theL_(m) and L_(r) and the electrical efficiency that is delivered/achievedby circuit 24. While an L-L core with nested windings transformerstructure is shown and described in more detail below, it is recognizedthat other separable transformer geometries that can be assembled anddisassembled through motion on a single axis can be implementedaccording to additional embodiments of the invention. Beneficially,embodiment of the invention—based on the inclusion of LLC resonantconverter circuit 24 in inductive charger station 12 and inductive powerreceiver 16—is thus able to deliver 94% or greater charging efficiency(e.g., 94-97%), providing an effective, robust, hands-free, inductivecharging solution, when constructed in this way.

Referring now to FIGS. 3-8, a construction of the inductive chargerstation 12 and the inductive power receiver 16 on vehicle 14 are shownin greater detail, according to various views thereof. The constructionof the inductive charger station 12 and the inductive power receiver 16are such that a physical arrangement of circuit elements therein may beachieved via self-aligning of the transformer halves (i.e., primary andsecondary sides 40, 54) during parking or docking without frictionloading the insulation covering electronic elements, and while stillobtaining a very close tolerance assembly in the active regions. Whileinductive charger station 12 is described here below as a rotatablecharging station movable between an upright charging position and alowered storage position—including a distinct docking head 60, basecomponent 62, and pivot member 64, with the pivot member allowing forsuch rotation—it is recognized that embodiments of the invention are notto be limited to this specific structure. That is, according to anotherembodiment, the inductive charger station 12 may be constructed as apedestal dock that permanently remains in an upright charging positionand is not capable of rotating down to a folded storage position (i.e.,no pivot member 64 to provide for such rotation). Accordingly, it isunderstood that embodiments of the invention are not to be limitedstrictly to the specific charger station 12 construction described herebelow.

As shown first in FIGS. 3-7, the inductive charger station 12 isgenerally composed of a docking head 60, a base component 62, and apivot member 64—with the inductive charger station 12 also including ahousing 66 for storing the docking head 60, base component 62, and pivotmember 64 when in a down position. The docking head 60 is composed of acontoured body 68—including one or more protrusions 69 extending outtherefrom—that is shaped to mate with a cavity 70 formed in inductivepower receiver 16, with an exemplary embodiment of the docking head 60including a pair of protrusions 69 formed thereon. A ferrite transformercore 72 is affixed to (and housed within) the body 68 and has primarywindings 50 of the transformer 42 (FIG. 2) wound thereon. The ferritetransformer core 72 is formed from one or more L-shaped legs or members74, with two legs 74 being shown in the illustrated embodiment. In anembodiment where the core 72 comprises two legs 74, the pair of legs 74collectively form an “L-L core.” According to an exemplary embodiment,the L-L core 72 has nested windings 50 wound thereon that are split onthe two legs 74 to form a transformer pair (i.e., two transformer 42)that can operate in an interleaved fashion. However, it is recognizedthat the core 72 could be populated with only a single transformer(i.e., windings 50 on only one leg 74), according to another embodimentof the invention, so as to produce half power as compared to the twotransformer arrangement (e.g., 3.6 kW vs. 7.2 kW). The contoured body68, as well as the transformer core 72 and primary winding legs 74 oftransformer 42, are covered with a protective coating or covering 76,such as an electrically insulating and durable polymer/plastic material,having an appropriate wall thickness (e.g., 2 mm). Additionally, thecovering 76 provided over primary windings 50 and transformer core legs74 may be tapered so as to fit into the receptacles 78 of inductivepower receiver 16 to enable a very close and repeatable positioningbetween the primary and secondary windings 50, 52 of the transformer 42while experiencing minimal sliding friction or abrasion, as will beexplained in greater detail below.

In one embodiment, docking head 60 further includes a communicationsconnection 79 that provides for alignment verification of the dockinghead 60 with the inductive power receiver 16 and provides redundantcommunication about battery bus voltage and current. The communicationsconnection may comprise an optical, infrared or other near-fieldcommunications port that communicates with a corresponding optical,infrared, or other near field communications port on the inductive powerreceiver 16 to form a communications path therebetween, therebyverifying alignment between the components and allowing for voltagecontrol to regulate the charge/voltage going into the battery of theelectric vehicle.

As shown in FIG. 5, in one embodiment, docking head 60 further includesa pair of heat sinks 80 mounted to the L-L core 72 to provide cooling tothe transformer 42. The heat sinks 80 are mounted to a back surface ofthe core legs 74, opposite from the protrusion about which windings 50are wound, so as to draw heat from the core legs 74. In an exemplaryembodiment, a heat pipe 82 is integrated with each heat sink 80 toprovide additional cooling capability. A cooling fluid is circulatedthrough the heat pipe 82 to remove additional heat from core legs 74,thereby keeping the transformer 42 cool while transferring power throughthe requisite layers of plastic 76 on docking head 60 (and inductivepower receiver 16). While not shown in FIG. 5, it is recognized that oneor more air moving devices—such as fans or synthetic jet actuators—maybe positioned adjacent heat sinks 80 to increase the rate of coolingprovided from heat sinks 80 and heat pipes 82.

As shown in FIG. 4, the base component 62 of inductive charger station12 generally includes a central region 84 that houses the packagedelectronics of power conversion circuitry (i.e., MOSFETS 34 andcontroller 38 of LLC resonant circuit 24, FIG. 2) of the inductivecharger station 12, and a pair of convective heat sinks 86 positioned onopposing sides of the central region 84. The heat sinks 86 and centralregion 84 collectively form a box-shaped base component 62, with theheat sinks 86 configured to support a load that might be applied downonto inductive charger station 12 when the inductive charger station 12is folded flat to its down position at ground level. According to anembodiment where an interleaved transformer pair is provided on the L-Lcore 72 of docking head 60, both of the heat sinks 86 may provideconvective cooling to the DC-DC power conversion circuitry (i.e., LLCresonant converter circuit 24, FIG. 2) housed in base component 62. Inan alternative embodiment, one of heat sinks 86 may provide convectivecooling to the DC-DC power conversion circuitry housed in base component62, while the other heat sink 86 may provide convective cooling for apower factor correction boost operation, such as for 3 kW power provideddirect from an AC source in shaded applications.

The docking head 60 is mounted to base component 62 via a springsuspended post 88 that extends therebetween. The post 88 allows for alimited degree of rotation or movement of the docking head 60 relativeto the base component 62, so as to allow for slight adjustments of thedocking head 60 position/orientation when mating with the inductivepower receiver 16. As an example, the post 88 allows for a wobble of thehead 60 to accommodate assembly tolerance and suspension motion as thevehicle 14 is unloaded, as will be explained in further detail below.

As shown in FIGS. 4, 6, and 7, pivot member 64 allows for rotation ofthe inductive charger station 12 (i.e., of docking head 60 and basecomponent 62) between a down position and an upright position. The pivotmember 64 is affixed to a bottom edge of base component 62 and iscylindrical in shape, with the member including an end cap 90 thereonhaving a pivot hole 92 and pin 94 thereon to selectively enable andinhibit rotation of the pivot member 64 and inductive charger station 12as a whole. The pivot member 64 may be rotated via any of a number ofsuitable methods, such as via an electromechanical motor or component(not shown) housed in pivot member 64 that effects the rotation, or viaan actuator member or plate 103 (that may include, for example, a stiffspring) that causes a pivoting of the pivot member 64 responsive to theweight of the vehicle 14 driving over the member (but not to lighterweights, such as the weight of people and pets, for example).

In operation of inductive charger station 12, the pin 94 of pivot member64 may be selectively engaged and disengaged with end cap 90 to enableand inhibit rotation of the inductive charger station 12 to its uprightposition. That is, when pin 94 is engaged, rotation of the inductivecharger station 12 is enabled, and the pivot member 64 may cause basecomponent 62 to rotate responsive to actuation of the pivot member by anelectromechanical motor or a weight of the vehicle. When the pin 94 isnot engaged, rotation of the inductive charger station 12 is inhibited,with the pivot member 64 undergoing a “free rotation” that does notengage base component 62 and result in a corresponding rotation thereof.To cause movement of the pin 94 to the engaged position, any of avariety of means can be employed, including for example a solenoid orphase change wax that causes movement of the pin 94 to the engagedposition.

It is recognized that system controls may be employed to unlock theinductive charger station 12 from its down position and be raised to theupright position for the correct vehicle. In a highly controlledenvironment, such as a garage, no lock may be needed, and thus no strictsystem controls may be necessary—such that the weight of electricvehicle 14 itself is the only input required for “unlocking” of theinductive charger station 12—with the weight of electric vehicle 14causing compression of the actuator member 103 and a correspondingrotation of the inductive charger station 12 to the upright position, aspreviously explained. In another embodiment, communication between theelectric vehicle 14 and the inductive charger station 12 may be requiredto unlock the inductive charger station 12. That is, a wireless signalmay be transmitted from the vehicle 14 to inductive charger station 12that identifies itself as a vehicle authorized to receive a charge fromthe inductive charger station 12. Upon receipt of the wireless signal,the inductive charger station 12 may then be unlocked and rotation ofthe inductive charger station 12 to the upright position is allowed—withsuch rotation being provided by an electromechanical motor that isactivated upon receipt of the vehicle identification signal or by theinteraction of the vehicle 14 with the actuator member 103 of theinductive charger station 12.

With regard to the outer housing 66 of inductive charger station 12,FIG. 6 illustrates the inductive charger station 12 in its down positionand the construction of housing 66, according to an exemplaryembodiment. As can be seen, housing 66 is constructed to have agenerally flat profile, with bezeled side surfaces 96 (at no more than a15° angle, for example) leading up to a flat top cover or surface 98,such that the inductive charger station 12 extends only a minimaldistance above ground level, such as 2.5 inches for example. The bezeledsurfaces 96 surround an interior cavity 100 that houses the docking head60, base component 62, and pivot member 64, with the moveable cover 98being provided over cavity 100 that protects the docking head 60, basecomponent 62, and pivot member 64 from the environment when theinductive charger station 12 is in the down position and the cover 98 isclosed. The bezeled surfaces 96 of housing 66 allow for a vehicle toeasily drive over the inductive charger station 12 and minimize itsfootprint on the surrounding environment. In one embodiment, where aseparate wall mounted AC-DC boost converter is not present in thecharging system 10 (FIG. 1A), a power feed may be provided on one of thebezeled surfaces 96, and the housing 66 may house AC-DC power conversionelements therein (i.e., AC to ˜400 V DC conversion), such that theinductive charger station 12 may be directly connected to an AC source.

While inductive charger station 12 and housing 66 thereof is shown asextending above ground and defining a cavity 100 within which dockinghead 60, base component 62, and pivot member 64 are housed, it isrecognized that alternative embodiments of the invention may beimplemented where the inductive charger station 12 is flush with theground. In such an embodiment, a cavity may be formed in the ground toreceive the docking head 60, base component 62, and pivot member 64,thereby further minimizing the footprint of the inductive chargerstation 12 on the surrounding environment.

Additionally, according to one embodiment of the invention, a weight ofelectric vehicle 14 driving onto the inductive charger station 12 (e.g.,onto the actuator member or plate 103 of the charger) may cause a chockor curb-like structure 101 to be raised up from ground as part ofhousing 66 or adjacent to housing 66, as shown in FIGS. 6 and 7. Thechock 101 may raise up from the ground upon the weight of the vehicle 14being applied to the actuator plate 103, which in turn actuates pins 94of end caps 90. That is, upon a tire pressing down on the plate 103, thepins 94 are forced to traverse down along kidney shaped slots (thatfollow a radius around the pins 94 around which pivot member 64 andpivot member 107 rotate) formed in housing 66 and plate 103, whichcauses the covers 98 to open and present the charger 12 and also causesthe chock 101 to rotate up around a same center of rotation as the pivotmember 64. The chock 101 functions as a stop for the vehicle 14 when thevehicle is being aligned with the inductive charger station 12—eithervia a manual alignment performed by the driver or via an automaticalignment performed by an autonomous vehicle. The chock 101 may thenretract back into the ground upon the vehicle 14 disengaging from theinductive charger station 12. According to one embodiment, a surfacecover 96 located in-board of the wheel of vehicle 14 may also rotate upupon the weight of the vehicle 14 being applied to actuator plate 103,such that the wheel is secured on two sides thereof.

Referring now to FIG. 8, a structure of the inductive power receiver 16on electric vehicle 14 is illustrated in greater detail. The inductivepower receiver 16 generally comprises a housing 102 and powerelectronics circuitry (as illustrated in FIG. 2) that provide forreceiving of and interaction with inductive charger station 12. Thehousing 102 defines a cavity 70 for receiving docking head 60therein—including one or more receptacles 78 configured to receive theone or more protrusions 69 of the docking head 60. In an exemplaryembodiment, a pair of receptacles 78 are provided in housing 102 thatare similar in appearance to a dual exhaust on an internal combustionengine. The receptacles 78 receive the protrusions 69 of the dockinghead and the legs 74 of L-L transformer core 72 therein (or only asingle L core) for positioning of the primary windings 50 in closeposition to the secondary windings 52 of inductive power receiver 16,with the secondary windings 52 encircling the receptacles 78 such thatthey are placed next to primary windings 50. That is, the receptacles 78are configured to accept the primary halves of the transformers 42 ofinductive charger station 12 that can operate in an interleaved fashion,or can accept the single transformer 42 of inductive charger station 12,with no discernible difference to an observer. While not shown in FIG.7, it is recognized that inductive power receiver 16 includes thereintransformer core halves/legs (i.e., an L-L core) that corresponds withthe L-L core 72 of inductive charger station 12, with the core beingincorporated within housing 102.

Similar to the protrusions 69 of the docking head 60, receptacles 78 (aswell as the transformer core halves/legs surrounding receptacles 78),are covered with a protective coating or covering 76, such as anelectrically insulating and durable polymer/plastic material, having anappropriate wall thickness (e.g., 2 mm). According to one embodiment ofthe invention, the coating 76 covering each of protrusions 69 andreceptacles 78 (or just one of the components) may be formed of anultra-high molecular weight polyethylene that reduces friction duringalignment/mating of the protrusions 69 with receptacles 78. According toanother embodiment, rollers may be integrated into (on or just under thesurface) protrusions 69 and/or receptacles 78 to provide frictionreduction between protrusions 69 and receptacles 78 duringalignment/mating thereof. Via use of such coating materials and/orrollers, wear on the docking head 60 of inductive charger station 12 andthe inductive power receiver 16 can be minimized, so as to increase thelongevity of these components.

For properly aligning the receptacles 78 of inductive power receiver 16with the L-L core 72 and the primary winding(s) 50 of docking head 60, aset of alignment features are provided on housing 102 that—when actingtogether—form a funnel for motion in a plane parallel to the ground. Thealignment features include a flat section 104 and a tapered section 106that are fed with a stepped taper section 108. The alignment featuresalso include a substantially planar downward facing reference surface110 fed with a radius or a gradual funnel 112 that can push the dockinghead 60 of the inductive charger station 12 down to align transformerelements (i.e., primary and secondary transformer components).Additionally, according to an exemplary embodiment, inductive powerreceiver 16 includes a communications connection 113 (e.g., optical,infrared or other near-field communications port) on housing 102 thatinteracts with communications connection 79 on docking head 60 toprovide for alignment verification therebetween and providecommunication about battery bus voltage and current in the electricvehicle 14, so as to regulate the charge/voltage going into the batterythereof.

The alignment features of the inductive power receiver housing 102correspond with a set of alignment features on the docking head 60, withsuch features on the docking head 60 being formed along the top andfront portions thereof that most closely interact with the inductivepower receiver 16. Specifically, a flat portion 114 and a taper portion116 (FIG. 4) are formed on sides of docking head 60 that act incombination with a spring centered travel feature (i.e., post 88) tofollow the stepped taper 108 of inductive power receiver housing 102,thereby accommodating left-to-right misalignment of the vehicle 14 withrespect to the inductive charger station 12 (e.g., up to 3 inches ofmisalignment) and properly locating the mating parts of the head andreceiver housing before nesting occurs, with only one degree of freedomremaining for the last 40-50 mm of travel of the head/receiver. Thealignment features on the docking head 60 also include a substantiallyflat top 118 that obtains planar alignment with the inductive powerreceiver housing 102 before the electronically active part of thedocking head 60 mates with the receiver 16. This alignment isfacilitated by a nose down natural position of the docking head 60, sothat when the radius 112 on the inductive power receiver housing 102contacts the docking head 60, the head 60 pivots up to match the planarorientation of the receiver 16. Simultaneously the spring suspended post88 of docking head 60 moves to accommodate any variation in vehicleheight. The tapered covers over the primary windings 50 therefore arealigned to fit into the dual exhaust-like receptacles 78 of inductivepower receiver 16, such that the primary and secondary windings 50, 52are positioned in a very close and repeatable relationship, whileexperiencing no sliding friction or abrasion therebetween.

As indicated above, the alignment features present on the inductivecharger station 12 (i.e., docking head 60) and inductive power receiver16 may accommodate misalignment therebetween upon to a certainamount/distance, such as up to 3 inches of misalignment. Thus, it isrecognized that in order for the electric vehicle 14 to successfullyreceive inductive charging, it is necessary to be able to bring theinductive power receiver 16 into substantial alignment with theinductive charger station 12 in a reliable and repeatable fashion.According to embodiments of the invention, to achieve such alignment,the electric vehicle 14 is in the form of an autonomous vehicle (alsoknown as a driverless car, auto, self-driving car, robotic car, etc.),which is understood to refer to a vehicle that is capable of sensing itsenvironment and navigating without human input.

Referring now to FIG. 9, an autonomous electric vehicle that mayincorporate inductive power receiver 16 and be utilized to providealignment with the inductive charger station 12 is illustrated accordingto one embodiment. To function as an autonomous vehicle, the vehicle 14may have one or more computing devices, such as computing device 122containing one or more processors 124, memory 126 and other componentstypically present in general purpose computing devices. In one example,computing device 122 may be an autonomous driving computing systemincorporated into vehicle 14. The autonomous driving computing systemmay be capable of communicating with various components of the vehicle.For example, referring to FIG. 9, computing device 122 may be incommunication with various systems of vehicle 14, such as decelerationsystem 128, acceleration system 130, steering system 132, signalingsystem 134, navigation system 136, positioning system 138, and detectionsystem 140 in order to control the movement, speed, etc., of vehicle 14in accordance with instructions provided in memory 126. While thesesystems are shown as external to computing device 122, in actuality,these systems may be incorporated into computing device 122, again as anautonomous driving computing system for controlling vehicle 14.

As an example, computing device 122 may interact with decelerationsystem 128 and acceleration system 130 in order to control the speed ofthe vehicle. Similarly, steering system 132 may be used by computer 122in order to control the direction of vehicle 14. For example, if vehicle14 is configured for use on a road, such as a car or truck, the steeringsystem may include components to control the angle of wheels to turn thevehicle. Signaling system 134 may be used by computing device 122 inorder to signal the vehicle's intent to other drivers or vehicles, forexample, by lighting turn signals or brake lights when needed.

Navigation system 136 may be used by computing device 122 in order todetermine and follow a route to a location. In this regard, thenavigation system 136 and/or data 134 may store detailed mapinformation, e.g., highly detailed maps identifying the shape andelevation of roadways, lane lines, intersections, crosswalks, speedlimits, traffic signals, buildings, signs, real time trafficinformation, vegetation, or other such objects and information.

Positioning system 138 may be used by computing device 122 in order todetermine the vehicle's relative or absolute position on a map or on theearth. For example, the position system 138 may include a GPS receiverto determine the device's latitude, longitude and/or altitude position.Other location systems such as laser-based localization systems,inertial-aided GPS, or camera-based localization may also be used toidentify the location of the vehicle. The location of the vehicle mayinclude an absolute geographical location, such as latitude, longitude,and altitude as well as relative location information, such as locationrelative to other cars immediately around it which can often bedetermined with less noise than absolute geographical location.

The positioning system 138 may also include other devices incommunication with computing device 122, such as an accelerometer,gyroscope or another direction/speed detection device to determine thedirection and speed of the vehicle or changes thereto. By way of exampleonly, an acceleration device may determine its pitch, yaw or roll (orchanges thereto) relative to the direction of gravity or a planeperpendicular thereto. The device may also track increases or decreasesin speed and the direction of such changes. The device's provision oflocation and orientation data as set forth herein may be providedautomatically to the computing device 122, other computing devices andcombinations of the foregoing.

The detection system 140 also includes one or more components fordetecting objects external to the vehicle such as other vehicles,obstacles in the roadway, traffic signals, signs, trees, etc. Forexample, the detection system 138 may include lasers, sonar, radar,cameras and/or any other detection devices that record data which may beprocessed by computing device 122. In the case where the vehicle is asmall passenger vehicle such as a car, the car may include a laser orother sensors mounted on the roof or other convenient location. In anexemplary embodiment, the detection system 140 specifically includes arearview camera sighting mechanism that allows a human driver have aline-of-sight and viewing of objects behind the vehicle, so as to enableto the driver to be aware of a positioning of such objects and thepositioning of the car relative thereto.

The computing device 122 may control the direction and speed of thevehicle by controlling various components. By way of example, computingdevice 122 may navigate the vehicle to a destination location completelyautonomously using data from the detailed map information and navigationsystem 136. Computer 122 may use the positioning system 138 to determinethe vehicle's location and detection system 140 to detect and respond toobjects when needed to reach the location safely. In order to do so,computer 122 may cause the vehicle to accelerate (e.g., by increasingfuel or other energy provided to the engine by acceleration system 130),decelerate (e.g., by decreasing the fuel supplied to the engine,changing gears, and/or by applying brakes by deceleration system 128),change direction (e.g., by turning the front or rear wheels of vehicle14 by steering system 132), and signal such changes (e.g., by lightingturn signals of signaling system 134). Thus, the acceleration system 130and deceleration system 130 may be a part of a drivetrain that includesvarious components between an engine of the vehicle and the wheels ofthe vehicle. Again, by controlling these systems, computer 122 may alsocontrol the drivetrain of the vehicle in order to maneuver the vehicleautonomously.

Accordingly, based on operation of computing device 122—and thecontrolling of various vehicle systems 128-140 performed thereby—theautonomous electric vehicle 14 is able to navigate to the inductivecharger station 12 and determine the positioning of the vehicle relativeto the inductive charger station 12. More specifically, upon arriving atthe charging system 10 (FIGS. 1A and 1B) and the inductive chargerstations 12 present thereat, the autonomous electric vehicle 14 mayemploy the detection system 140—including one or more cameras thereof,such as a rearview camera—to provide visual tracking of the docking head60 in the upright position. The autonomous vehicle 14 may then functionto place itself into alignment in relation to inductive charger station12 to enable mating of the docking head 60 and the inductive powerreceiver 16. The autonomous electric vehicle 14 may then control itselfto come into contact with the inductive charger station 12 without anyadditional automated movement of the inductive charger station 12 oncein the upright position, at which time the alignment features present onthe inductive charger station 12 (i.e., docking head 60) and inductivepower receiver 16 may accommodate any slight misalignment therebetweenin order to provide for a smooth nesting of the tapered covers 76 onprimary windings 50 into the dual exhaust-like receptacles 78 withoutany friction or wear therebetween.

While description in provided above regarding autonomous operation ofthe electric vehicle to align and mate inductive power receiver 16 withthe inductive charger station 12, i.e., operation/functioning of theelectric vehicle as a “positioning robot”, it is recognized thatautonomous operation of an electric vehicle may also be employed toprovide for other types of charging of the electric vehicle. That is,according to other embodiments of the invention, the electric vehiclemay be operated in an autonomous manner (as described in detail above)in order to enable “hot contact charging” or other forms of DC fastcharging for the electric vehicle. As one example, the electric vehiclemay be operated in an autonomous manner to provide alignment and matingof a plug receptacle on the vehicle and a pronged charging station—withsuch autonomous charging beneficially enabling safe energizing of aseries of autonomous vehicles that charge one after another, returningto a non-electrified (less expensive) parking spot after the desiredstate of battery charge is obtained. Accordingly, it is to be understoodthat autonomous operation of the electric vehicle for enabling chargingthereof is not limited only to inductive chargingstructures/arrangements.

Beneficially, embodiments of the invention thus provide a hands-free,ground-level, electric vehicle docking, inductive charging system thatcombines the best attributes of inductive charging (no exposed valuableflexible cords, or galvanic contacts to spark, wear or degrade, lowprofile/near ground level, clutter free, aesthetically pleasing form)with the best attributes of corded chargers (high efficiency, low on-carweight). The inductive charging system provides an efficient solutionfor night charging of electric vehicles at apartments and/or otherpublic areas, thus providing high public benefit with minimum publicinfrastructure expense.

The design of the LLC battery charger in the inductive chargingsystem—i.e., integrated magnetic with a split transformerdesign—delivers battery charging efficiencies of 94% or greater (e.g.,96.6% DC-DC efficiency at 2.64 kW peak power), while reducing the weightof the required charging components on the vehicle. The LLC batterycharger is designed as a modular charger, in that one or twotransformers (cores and associated windings) may be present in each of astationary inductive charger station (transformer primary side) andvehicle-mounted inductive power receiver (transformer secondary side) ofthe inductive charging system—with the stationary inductive chargerstation and vehicle-mounted inductive power receiver constructed to havetwo nesting areas for cores and windings that may be selectivelypopulated with no discernible difference to an observer. The modularcharger thus provides for inductive charging via a single transformer ora pair of interleaved primary transformer halves, where one transformerdelivers 3 to 6 kW and the other transformer also delivers 3 to 6 kW,causing the pair to deliver 6 to 12 kW—with 3.6/7.2 kW and 5/10 kWdeliveries being suitable power levels provided by the transformerhalves, for example. Additionally, the inductive charging systemaccommodates charging for electric vehicles with various bus voltages,with electric vehicles having battery bus voltages of 400 V or 800 Vbeing accommodated by the inductive charging system.

Additionally, the inductive LLC battery charger provides such chargingcapabilities while adding only minimal weight to the electric vehicle(based on the split transformer construction of the LLC batterycharger), with the inductive power receiver on the electric vehiclehaving a weight of approximately 5 pounds or less (e.g., ˜5 lb for a7.2-10.0 kW interleaved transformer charger and <3 lb for a 3.6-5.0 kWsingle transformer charger).

Still further, the inductive charging system beneficially makes use ofemerging autonomous vehicle capability to provide for accurate andrepeatable mating of the electric vehicle with the inductive chargerstation. The autonomous electric vehicle navigates to the inductivecharger station and determines the positioning of the vehicle relativeto the inductive charger station, with the electric vehicle then causingitself to come into contact with the inductive charger station in anautonomous manner, without any input/navigating from the driver andwithout any automated movement of the inductive charger station 12 (oncein its upright position). Such autonomous mating of the electric vehiclewith the inductive charger station provides a smooth nesting of theinductive charger station with the inductive power receiver of theelectric vehicle.

Therefore, according to an embodiment of the invention, a chargingsystem for charging an electric vehicle comprises aninductor-inductor-capacitor (LLC) battery charger that includes anisolation transformer having a transformer primary and a transformersecondary, the transformer primary included in an inductive chargerstation of the charging system and the transformer secondary included inan inductive power receiver of the charging system, with the inductivepower receiver positioned on the electric vehicle. The LLC batterycharger also includes a magnetizing inductor circuit element and aleakage inductor circuit element integrated into the isolationtransformer on the transformer primary. The isolation transformer isconstructed such that the transformer primary and the transformersecondary are separable from one another, with a selective engaging anddisengaging of the transformer primary and the transformer secondarybased on movement of the inductive power receiver on the electricvehicle relative to the inductive charger station.

According to another embodiment of the invention, a charging system forinductively charging an electric vehicle comprises an inductive chargerstation including a docking head comprising a transformer primary havinga magnetizing inductor circuit element and a leakage inductor circuitelement integrated therein and a base component coupled to the dockinghead, the base component comprising power conversion circuitryconfigured to provide a conditioned input power to the transformerprimary. The charging system further comprises an inductive powerreceiver separate from the inductive charger station, the inductivepower receiver including a transformer secondary selectively mateablewith the transformer primary based on movement of the inductive powerreceiver relative to the inductive charger station and a rectificationcircuit configured to provide a conditioned DC output power forrecharging the electric vehicle.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. An inductive charger station for charging anelectric vehicle, the inductive charger station comprising: a dockinghead including a body covered by an electrically insulating coating, thebody including one or more tapered protrusions extending out therefrom;and a transformer primary that includes one or more transformer coreseach having a primary winding wound thereabout, each of the one or moretransformer cores positioned within the body and extending into arespective one of the one or more tapered protrusions, the transformerprimary configured to provide power to a transformer secondary of aninductive power receiver positioned on an electric vehicle, with aselective engaging and disengaging of the transformer primary and thetransformer secondary based on movement of the inducive power receiveron the electric vehicle relative to the inductive charger station;wherein the transformer primary comprises a pair of transformer coreseach having a primary winding wound thereabout, so as to form atransformer pair, and wherein the transformer pair operates in aninterleaved fashion.
 2. The inductive charger station of claim 1,further comprising: a magnetizing inductor circuit element and a leakageinductor circuit element integrated into the transformer primary.
 3. Theinductive charger station of claim 1, wherein the docking headcomprises: a heat sink positioned within the body and mounted to each ofthe one or more transformer cores on a back side thereof; and a heatpipe integrated with the heat sink to provide additional coolingcapability to the transformer primary.
 4. The inductive charger stationof claim 1, wherein the electrically insulating coating that covers theone or more tapered protrusions and the one or more transformer coresand primary winding positioned therein causes a separation between thetransformer primary and the transformer secondary so as to create aleakage inductance, and wherein the leakage inductor circuit elementintegrated into the isolation transformer operates to enable usage ofthe leakage inductance to establish resonance between the transformerprimary and the transformer secondary.
 5. The inductive charger stationof claim 1, wherein the inductive power receiver comprises a housingdefining a cavity configured to receive the docking head therein, thehousing including one or more receptacles that receive the one or moretapered protrusions of the docking head therein; and wherein one or moresecondary windings of the transformer secondary are positioned about theone or more receptacles such that the primary winding on each of the oneor more transformer cores of the transformer primary are positioned inclose position to the one or more secondary windings upon positioning ofthe one or more tapered protrusions within the one or more receptacles.6. The inductive charger station of claim 5, wherein each of the dockinghead and the housing of the inductive power receiver include a set ofalignment features thereon that collectively form a funnel for motion ina plane parallel to the ground, to align the docking head and theinductive power receiver, the set of alignment features including one ormore of flat sections, tapered sections, and radius or funnel surfaces.7. The inductive charger station of claim 5, wherein the inductivecharger station and the inductive power receiver include communicationsconnections thereon operable with one another to provide alignmentverification of the docking head with the cavity of inductive powerreceiver and to provide electric vehicle battery bus voltage and currentinformation, the communications connections comprising one of anoptical, infrared, or near-field communications port.
 8. The inductivecharger station of claim 5, wherein the electrically insulating coatingon the one or more protrusions and/or the one or more receptaclescomprises an ultra-high molecular weight polyethylene coating and/orwherein the one or more protrusions and/or the one or more receptaclescomprises rollers integrated therein, with each of the ultra-highmolecular weight polyethylene coating and the rollers reducing frictionduring alignment and mating of the one or more protrusions with the oneor more receptacles.
 9. The inductive charger station of claim 1,further comprising: a base component coupled to the docking head via apost, so as to provide for limited movement of the docking head relativeto the base component; and a pivot member coupled to the base componenton an end thereof opposite the docking head, the pivot member configuredto rotate the inductive charger station between an upright position thatprovides for mating of the docking head with the inductive powerreceiver and a down position that provides for storage of the inductivecharger station.
 10. The inductive charger station of claim 9, furthercomprising: a housing including: a plurality of bezeled surfacessurrounding an interior cavity, the interior cavity housing the dockinghead, base component, and pivot member when in the down position; and amoveable cover positioned over the interior cavity, so as to protect thedocking head, base component, and pivot member when in the downposition.
 11. The inductive charger station of claim 1, furthercomprising: an AC-DC power converter coupleable to an AC utility feedcircuit breaker panel to receive AC power therefrom and convert the ACpower to DC power; and a DC bus connected to the AC-DC power converterto receive the DC power therefrom; wherein the inductive charger stationis coupled to the DC bus to receive the DC power therefrom.
 12. Theinductive charger station of claim 11, wherein the AC-DC power convertercomprises a 12 kW AC to 400 V DC wall-mounted panel.